Alice is not bound by her promise
In civil-legal-system, unilateral promises are enforceable. A contract does not require reciprocal consideration, and therefore, even if John’s promise to not break the law amounts to nothing, Alice’s promise has to be looked at.
Yet, if Alice consented under "violence", then her promise is void (article 1130 du Code Civil). "Violence" is defined at article 1140:
Il y a violence lorsqu'une partie s'engage sous la pression d'une contrainte qui lui inspire la crainte d'exposer sa personne, sa fortune ou celles de ses proches à un mal considérable.
There is violence when either party commits under a constraint that makes him or her fear to expose his or her person or wealth or that of others to a large danger.
Clearly, Alice only promised John $1000 under the threat of having her car stolen, hence her consent is void. John has no legal recourse against Alice in scenario 2A, neither for the money she promised her, nor for any actions he took in reliance of that (void) promise.
John is guilty of extortion in all scenarios
Code Pénal, article 312-1:
L'extorsion est le fait d'obtenir par violence, menace de violences ou contrainte soit une signature, un engagement ou une renonciation, (...)
Extorsion is when one obtains by violence, threat of violence of constraint either a signature, a promise or renunciation, (...)
In all scenarios, John has obtained a promise for money by his threat to steal the car. It does not matter that actually obtains money or a car, or that he intended to steal the car and only switched to extortion in the heat of the moment.
Alice can claim compensation for anything John took
Civil liability comes from a three-prong test of 1. fault, 2. damage, and 3.connection between fault and damage.
Per the above, John’s conduct is illegal (1). Any money or property that changes hand in the various scenarios does so as an immediate consequence of John’s actions (3), and to Alice's detriment (2).
Therefore, John has civil liability at least for the value of the car and/or $1000 that he obtained from Alice.
If Alice had additional expenses (such as moving her car into a guarded parking lot), I would expect those not to qualify, because there is no clear causal connection between those costs and John’s actions (3).